For a project with a 2x1 Roster schedule, should the roster calendar be assigned to activities or should only the resource availability be changed? I received a schedule where the calendar has been assigned to the activities with no resources assigned at all — effectively meaning no work happens every second week.

Overview:
This is a common and important misunderstanding in FIFO/Roster project scheduling. The short answer is: the Roster calendar should be assigned to resources, not to activities.

Why Assigning the Roster Calendar to Activities is Wrong:

When you assign a Roster calendar (e.g. 7 days ON / 7 days OFF) directly to an activity, P6 interprets this to mean the work itself cannot be performed every second week. This causes:

• Activity durations to effectively double


• The schedule to become unrealistic and misleading


• The roster logic to be misrepresented in the programme

If no resources are assigned either (as in the schedule described), the result is a programme where activities simply stop for a week every fortnight — which is almost never the intent.

Correct Approach in P6 for a 2x1 Roster:

• Step 1: Create a Roster calendar (e.g. 7 days ON, 7 days OFF) under Enterprise > Calendars > Resource Calendars


• Step 2: Assign this Roster calendar to the Resource, not the activity


• Step 3: Activities should retain the project or site calendar (e.g. 7 days/week, or 5 days/week depending on site conditions)


• Step 4: Assign the resources to activities as normal

P6 will then correctly calculate that the worker is only available every other week, while the activity itself can still be scheduled continuously if other resources are available.

Handling Two Rotating Crews (Full FIFO Coverage):

If you have two crews rotating on a 2x1 roster to provide continuous site coverage:


• Create two separate resources (e.g. Crew A and Crew B)


• Assign each resource a Roster calendar that is offset by one week


• Assign both resources to the same activities


• This accurately models 14/7 coverage with each crew working 7 days on / 7 days off

Reviewing the Schedule You Received:

The schedule described (Roster calendar on activities, no resources assigned) is incorrectly built. Key issues to address during review:


• Remove the Roster calendar from activities and revert to the site/project calendar


• Create properly configured resource calendars reflecting the roster pattern


• Assign resources to activities


• Validate activity durations after corrections — they may need to be halved

Summary:

Assignment Target | Calendar Type       | Purpose
------------------|---------------------|---------------------------
Activity          | Site/Project cal    | When work CAN be done
Resource          | Roster/Shift cal    | When the worker IS available

Keeping these two concerns separate is the foundation of accurate resource-loaded roster scheduling in P6.